Ps had been released from prison subject to a licence which was revoked when they breached the terms of the licence and the parol boards required them to return to prison and did not recommend that they be allowed to remain out of prison. There were no oral hearings. HL held that in resolving challenges to licence revocations the Parole Board had a public law duty to act in a procedurally fair manner. Although a public law hearing would not be required in every case, it was likely to be called for where facts were in issue that could affect the outcome or where it might otherwise contribute to achieving a just decision, as here. Lord Bingham sums this up in his judgment.